Sexually transmitted diseases (STDs) have made a comeback in China after their virtual eradication during the Mao era. Current levels of STDs provide a strong indication that a growing number of Chinese are engaging in high-risk sexual behaviors. The proposed project will investigate sexual behavior and sexual mixing patterns of Chinese adults through a cross-sectional sample survey of sexual behavior and sexual networks to be conducted among 3 populations in the Shanghai greater metropolitan area: the adult resident population, rural migrants and women working in entertainment establishments at risk of engaging in prostitution. Respondents will be asked to give details about themselves, their partners and the behavioral repertoires of their partnerships. They will also be asked to provide information on their health status and symptoms associated with STDs. Biomarkers (urine) will be collected from respondents who agree to provide them and assays performed to measure Chlamydia and gonorrhea. From the data thus obtained, we will derive empirically grounded, population-specific behavioral input parameters for use in mathematical models that will allow an exploration of the implications of sexual behaviors observed in Shanghai for the spread of STDs in the Chinese population at large. In addition, we propose to utilize the data collected towards the identification of key attributes of the social organization of sexual partnering in Shanghai, the understanding of the relationship between the organization of sexual partnering and differences in prevalence of STDs within and across populations, and the identification of epidemiologically relevant populations to the transmission and spread of STDs. [unreadable] [unreadable]